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Rudimentary gravity

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This commit is contained in:
Johan Maasing 2025-01-27 20:29:50 +01:00
parent a2f1e11af8
commit d6b3be83d5
3 changed files with 56 additions and 32 deletions
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28
main.cpp
View file

@ -2,16 +2,16 @@
#include <cstring> #include <cstring>
#include "simulation.h" #include "simulation.h"
void printGrid(simulation::SimulationGrid grid) void printGrid(simulation::SimulationGrid* grid)
{ {
std::cout << std::string(grid.x_max+2, '_') << std::endl; std::cout << std::string(grid->x_max+2, '_') << std::endl;
for (unsigned char y = grid.y_max; y > 0; y--) for (unsigned char y = grid->y_max; y > 0; y--)
{ {
std::cout << "|"; std::cout << "|";
for (unsigned char x = 0; x < grid.x_max; x++) for (unsigned char x = 0; x < grid->x_max; x++)
{ {
unsigned int offset = simulation::getCellOffset(x, y-1, 0, grid); unsigned int offset = getCellOffset(x, y-1, 0, grid);
unsigned int material = grid.out[offset]; unsigned int material = grid->out[offset];
switch (material) switch (material)
{ {
case simulation::VACUUM: case simulation::VACUUM:
@ -26,12 +26,12 @@ void printGrid(simulation::SimulationGrid grid)
} }
std::cout << "|" << std::endl; std::cout << "|" << std::endl;
} }
std::cout << std::string(grid.x_max+2, '_') << std::endl; std::cout << std::string(grid->x_max+2, '_') << std::endl;
} }
void initGrid(simulation::SimulationGrid grid) { void initGrid(simulation::SimulationGrid* grid) {
unsigned int offset = simulation::getCellOffset(0,1,0, grid); unsigned int offset = simulation::getCellOffset(0,2,0, grid);
grid.in[offset] = simulation::WATER; grid->in[offset] = simulation::WATER;
} }
int main() { int main() {
@ -50,11 +50,11 @@ int main() {
zMax zMax
}; };
initGrid(grid); initGrid(&grid);
step(0, grid);
for (int n=0; n< 2; n++) { for (int n=0; n< 2; n++) {
printGrid(grid); simulation::step(0, &grid);
printGrid(&grid);
prepareForNextStep(&grid);
} }
std::free(inCells); std::free(inCells);
std::free(outCells); std::free(outCells);

53
simulation.cpp
View file

@ -1,16 +1,17 @@
#include "simulation.h" #include "simulation.h"
#include <cstring>
namespace simulation namespace simulation
{ {
unsigned int getCellOffset( int getCellOffset(
unsigned char x, unsigned char x,
unsigned char y, unsigned char y,
unsigned char z, unsigned char z,
SimulationGrid grid) SimulationGrid* grid)
{ {
if (x < grid.x_max && y < grid.y_max && z < grid.z_max) if (x < grid->x_max && y < grid->y_max && z < grid->z_max)
{ {
unsigned int offset = x + y * grid.x_max + z * (grid.y_max * grid.x_max); int offset = x + y * grid->x_max + z * (grid->y_max * grid->x_max);
return offset; return offset;
} }
return -1; return -1;
@ -18,33 +19,55 @@ namespace simulation
void step( void step(
double millisecondsSinceLastStep, double millisecondsSinceLastStep,
SimulationGrid grid) SimulationGrid* grid)
{ {
for (unsigned char x = 0; x < grid.x_max; x++) for (unsigned char x = 0; x < grid->x_max; x++)
{ {
for (unsigned char y = 0; y < grid.y_max; y++) for (unsigned char y = 0; y < grid->y_max; y++)
{ {
for (unsigned char z = 0; z < grid.z_max; z++) for (unsigned char z = 0; z < grid->z_max; z++)
{ {
unsigned int offset = getCellOffset(x, y, z, grid); int offset = getCellOffset(x, y, z, grid);
unsigned int material = grid.in[offset]; unsigned int material = grid->in[offset];
switch (material) switch (material)
{ {
case WATER: case WATER:
if (y > 0)
{ {
unsigned int downOffset = getCellOffset(x, y - 1, z, grid); int downOffset = getCellOffset(x, y - 1, z, grid);
// Flow down if cell is empty // Flow down if cell is empty
if (grid.out[downOffset] == 0) if (downOffset >= 0 && grid->out[downOffset] == 0)
{ {
grid.out[downOffset] = material; grid->out[downOffset] = material;
grid->out[offset] = VACUUM;
} else
{
// Stay in the same location
grid->out[offset] = material;
} }
break;
}
case MERCURY:
{
break;
} }
default: default:
grid.out[offset] = material; {
grid->out[offset] = material;
}
} }
} }
} }
} }
} }
void prepareForNextStep(SimulationGrid* grid)
{
// Flip the buffers
unsigned int* inCells = grid->in;
grid->in = grid->out;
grid->out = inCells;
// Clear out buffer
size_t bufferSizeInBytes = sizeof(unsigned int) * grid->x_max * grid->y_max * grid->z_max;
std::memset(grid->out, VACUUM, bufferSizeInBytes);
}
} }

7
simulation.h
View file

@ -24,15 +24,16 @@ namespace simulation
void step( void step(
double millisecondsSinceLastStep, double millisecondsSinceLastStep,
SimulationGrid grid SimulationGrid* grid
); );
unsigned int getCellOffset( int getCellOffset(
unsigned char x, unsigned char x,
unsigned char y, unsigned char y,
unsigned char z, unsigned char z,
SimulationGrid grid); SimulationGrid* grid);
void prepareForNextStep(SimulationGrid* grid);
} }
#endif //SIMULATION_H #endif //SIMULATION_H